"Welfare suicides don't exist. Suicide is a mental health issue." That line, by the former Labour official Luke Bozier, pretty much sums up the standard rightwing response to the website Calum's List. According to its founders, the aim of Calum's List is "to list the number of deaths where welfare reform has alleged to have had some culpability, and to make the best effort possible to work towards reducing this death toll." Bozier's Twitter comments were a gloss on blogposts by The Spectator's Isabel Hardman and the Telegraph's Brendan O'Neill.

There's more than a whiff of Freud's "kettle logic" (I didn't borrow your kettle; when I borrowed the kettle it was already broken; when I returned the kettle it wasn't damaged) about the cluster of incompatible arguments that these three presented against Calum's List. Their principal claims were as follows. The suicides have not been caused by the changes, and therefore to mention them is an act of opportunistic exploitation; if suicides have been caused by the reforms, this is no reason to abandon them; the problem is not the reforms themselves but how they are managed (ie those forced back to work should be given adequate support); suicide is not a rational act, which means that it can have no political significance.

I don't wish to argue here about whether or not specific cases of suicide were caused by the new legislation. But I do want to contest the bizarre idea that, in principle, suicides could not be adduced as evidence against the changes in the welfare system. If people dying as a consequence of the implementation of measures cannot count as evidence that the legislation has detrimental effects, what would?

O'Neill displays a strangely judgmental attitude towards suicide, arguing suicide "is not a rational response to economic hardship; it is not a rational response to having your benefits cut". This is a spectacular case of missing the point: for many of those suffering from mental illnesses, the capacity to act rationally is impaired, which is one reason that they need to be protected. As for the idea that those returning to work should receive proper support, the lack of such support is the issue. Atos, the agency responsible for testing whether claimants are fit to work, has seen a large number of appeals against its judgments upheld. And who can have faith the government will properly support those returning to work when it entrusts the transition to a discredited agency such as A4e?

But there's a more general problem here. Some of the rightwing commentators condemning Calum's List have deplored the "politicisation" of mental illness, but the problem is exactly the opposite. Mental illness has been depoliticised, so that we blithely accept a situation in which depression is now the malady most treated by the NHS. The neoliberal policies implemented first by the Thatcher governments in the 1980s and continued by New Labour and the current coalition have resulted in a privatisation of stress. Under neoliberal governance, workers have seen their wages stagnate and their working conditions and job security become more precarious. As the Guardian reports today, suicides amongst middle-aged men are on the increase, and Jane Powell, chief executive of Calm, the Campaign Against Living Miserably, links some of this increase with unemployment and precarious work. Given the increased reasons for anxiety, it's not surprising that a large proportion of the population diagnose themselves as chronically miserable. But the medicalisation of depression is part of the problem.

The NHS, like the education system and other public services, has been forced to try to deal with the social and psychic damage caused by the deliberate destruction of solidarity and security. Where once workers would have turned to trade unions when they were put under increasing stress, now they are encouraged to go to their GP or, if they are lucky enough to be able to be get one on the NHS, a therapist.

It would be facile to argue that every single case of depression can be attributed to economic or political causes; but it is equally facile to maintain – as the dominant approaches to depression do – that the roots of all depression must always lie either in individual brain chemistry or in early childhood experiences. Most psychiatrists assume that mental illnesses such as depression are caused by chemical imbalances in the brain, which can be treated by drugs. But most psychotherapy doesn't address the social causation of mental illness either.

The radical therapist David Smail argues that Margaret Thatcher's view that there's no such thing as society, only individuals and their families, finds "an unacknowledged echo in almost all approaches to therapy". Therapies such as cognitive behaviour therapy combine a focus on early life with the self-help doctrine that individuals can become masters of their own destiny. The idea is "with the expert help of your therapist or counsellor, you can change the world you are in the last analysis responsible for, so that it no longer cause you distress" – Smail calls this view "magical voluntarism".

Depression is the shadow side of entrepreneurial culture, what happens when magical voluntarism confronts limited opportunities. As psychologist Oliver James put it in his book The Selfish Capitalist, "in the entrepreneurial fantasy society," we are taught "that only the affluent are winners and that access to the top is open to anyone willing to work hard enough, regardless of their familial, ethnic or social background – if you do not succeed, there is only one person to blame." It's high time that the blame was placed elsewhere. We need to reverse the privatisation of stress and recognise that mental health is a political issue.